Injection drug use has been the principal initial vector of the human immunodeficiency virus type 1 (HIV-1) into the heterosexual population. IDU transmission of HIV-1 has lead to increased rates of transmission into the heterosexual partners with a marked increase in maternal-fetal transmission. A model of syringe disinfection was developed with both HIV-1 infected and non-infected marker syringes employed. In vitro HIV-1 culture was accessed for whole blood sensitivity and after determination of insufficient sensitivity at usual transmissible blood volumes; polymerase chain reaction detection of HIV-1 genome and HLA genome was used for surrogate marker for potential infectivity. During this fiscal year final confirmatory HIV-1 in-vitro cultures were completed as well as statistical analysis of syringe data. Manuscript preparation is complete with submission of final version to The Journal of Acquired Immune Deficiency Syndrome.